This invention relates to techniques and methods utilized in laying underwater pipelines. More particularly, the invention relates to laying pipelines wherein continuous lengths of pipe are first spooled onto a reel carried by a vessel and are thereafter unspooled into the water as the vessel proceeds along the pipeline route.
The methods and techniques described herein are particularly suited for self-propelled types of reel pipe laying vessels. Suitable vessels which would be expected to use the methods and techniques described herein include drill ships and ore carriers converted to carry pipe spooling reels and related reel pipelaying equipment. One such self-propelled vessel constructed specifically as a reel-type pipe laying ship is described in the following U.S. patent applications:
U.S. Application Ser. No. 903,180, filed May 5, 1978 by Charles N. Springett, Dan Abramovich, Stanley T. Uyeda and E. John Radu;
U.S. Application Ser. No. 903,181, filed May 5, 1978 and U.S. Application Ser. No. 35,216, filed May 2, 1979 as a Continuation-in-Part of said Ser. No. 903,181, each by Stanley T. Uyeda, E. John Radu, William J. Talbot, Jr. and Norman Feldman.
The disclosures of the above-listed U.S. applications are incorporated herein in their entireties by reference as though fully set forth below.
The present application (and the inventive subject matter described and claimed herein) and the above-listed U.S. applications are all owned by Santa Fe International Corporation; hereafter the above-listed commonly owned applications will be referred to as "prior related Santa Fe applications".
Prior to the development by Santa Fe of the self-propelled reel ship known in the industry as "Apache" (the construction of which is substantially described in the above-listed prior related Santa Fe applications) and which is scheduled to begin commercial pipelaying operations in late summer of 1979, most known commercial reel type pipelaying vessels consisted of non-self-propelled barges towed by a tug. One portable pipelaying system designed and built by Santa Fe for use on small supply boat type vessels for laying small diameter pipelines (up to 4" I.D.) has been in commercial use off the coast of Australia since about July, 1978; this portable pipelaying system is described in U.S. Patent Application Ser. No. 909,260, filed May 24, 1978 by Stanley T. Uyeda and John H. Cha, and assigned to Santa Fe.
Other patents owned by Santa Fe directed to and describing one or more features of reel pipelaying vessels include:
U.S. Pat. No. 3,237,438, issued Mar. 1, 1966 to Prosper A. Tesson;
U.S. Pat. No. 3,372,461, issued Mar. 12, 1968 to Prosper A. Tesson;
U.S. Pat. No. 3,630,461, issued Dec. 28, 1971 to Daniel E. Sugasti, Larry R. Russell, and Fred W. Schaejbe;
U.S. Pat. No. 3,641,778, issued Feb. 15, 1972 to Robert G. Gibson;
U.S. Pat. No. 3,680,342, issued Aug. 1, 1972 to James D. Mott and Richard B. Feazle;
U.S. Pat. No. 3,712,100 issued Jan. 23, 1973 to Joe W. Key and Larry R. Russell; and
U.S. Pat. No. 3,982,402, issued Sept. 28, 1976 to Alexander Craig Lang and Peter Alan Lunde.